The purposes of this project are twofold. (1) To investigate the effect of parenteral nutrition on protein and fat metabolism, and, (2) To develop and utilize 15N as a tracer to measure protein synthesis rates to study the effect of TPN on protein metabolism in rats and man. Two groups of adult cancer patients will be studied who have operable tumors. Group I will continue to eat a house diet ad lib, Group II will receive TPN. Each group will receive a 15N glycine infusion preoperatively. During surgery, blood, urine and some tissue specimens will be obtained for subsequent analysis for 15N for determination of protein synthesis rates and also fatty acid content.